Rpi4 and ethernet, maximum cable length?

1st Official Post

    Hi,

    I have been using kodi/libreelec with wifi for some time but as it sometimes lags I decided to try a wired connection instead. However when I try to change connection type the eth0 just "blink" idle and then disappears and then returns later one just to disappear again. Anyone that knows what this could be?

    All cables between switch and rpi are cat6 (approx. 15m in total), it works just fine if I connect a 10m cat5e directly between the switch and the rpi. Is there a maximum lenght of ethernet cables that the rpi can handle? I plugged my laptop into the "port" in the wall and it works great, pings both internally and externally without any lost packages.

    All support is appreciated.

    /shrug

    Just to mention;

    There are few combinations of "CAT6" (and other CATx) cables.

    For example "shielded" vs "unshielded", "CAT6" vs CAT6E" and all combinations of these.

    Not all devices handle all types equally good.

    What do you mean with "All cables between switch and rpi are cat6" ? Multiple connections ? Or cables extended ? If a Cat 5 cable works, but Cat 6 not, I suspect the Cat 6 cable. Are you sure there isn't a cross cable used instead of a straight one? How old is the switch? A connection between Pi and switch requires a straight cable, although most modern switches can adapt to a cross-cable.

    • Official Post
    Quote from fjohnsen

    Can it be that the computer can handle the issues (incorrectly wired or faulty cables) but the rpi cant?

    No, Linux handles the Ethernet protocol perfectly. If your laptop can deal with the same Ethernet cable, check your router settings. Make the RPi a known and trusted device for the firewall (compare with your laptop settings).

    Quote from fjohnsen

    Hi,

    I have been using kodi/libreelec with wifi for some time but as it sometimes lags I decided to try a wired connection instead. However when I try to change connection type the eth0 just "blink" idle and then disappears and then returns later one just to disappear again. Anyone that knows what this could be?

    All cables between switch and rpi are cat6 (approx. 15m in total), it works just fine if I connect a 10m cat5e directly between the switch and the rpi. Is there a maximum lenght of ethernet cables that the rpi can handle? I plugged my laptop into the "port" in the wall and it works great, pings both internally and externally without any lost packages.

    All support is appreciated.

    /shrug

    For reference. I have this floating setup consisting of Pi 3b (27" computer screen) with LibreELEC 9.2.7 connecting over WiFi 40+ feet fromUbiquiti AP. Live TV works without any lag.